U.S. patent application number 14/763178 was filed with the patent office on 2015-12-31 for crystallized glass and method for manufacturing same.
This patent application is currently assigned to NIPPON ELECTRIC GLASS CO., LTD.. The applicant listed for this patent is NIPPON ELECTRIC GLASS CO., LTD.. Invention is credited to Nobuo FUNABIKI, Masahiro KOBAYASHI, Shuhei OGAWA, Hirokazu TAKEUCHI.
Application Number | 20150376052 14/763178 |
Document ID | / |
Family ID | 51391019 |
Filed Date | 2015-12-31 |
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United States Patent
Application |
20150376052 |
Kind Code |
A1 |
TAKEUCHI; Hirokazu ; et
al. |
December 31, 2015 |
CRYSTALLIZED GLASS AND METHOD FOR MANUFACTURING SAME
Abstract
What is achieved is an optical wavelength
multiplexer/demultiplexer not necessarily requiring the function of
adjusting the optical path. A value
(.DELTA.L.sub.max-.DELTA.L.sub.min)/L obtained by dividing a
difference between a maximum value .DELTA.L.sub.max and a minimum
value .DELTA.L.sub.min of .DELTA.L in a range of -40.degree. C. to
80.degree. C. by L is 8.times.10.sup.-6 or less where L represents
a length of a crystallized glass (1) at 30.degree. C. and .DELTA.L
represents a difference between a length (L.sub.t) of the
crystallized glass (1) at each of the temperatures and the length
(L) thereof at 30.degree. C.
Inventors: |
TAKEUCHI; Hirokazu;
(Otsu-shi, JP) ; OGAWA; Shuhei; (Otsu-shi, JP)
; FUNABIKI; Nobuo; (Otsu-shi, JP) ; KOBAYASHI;
Masahiro; (Otsu-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NIPPON ELECTRIC GLASS CO., LTD. |
Otsu-shi, Shiga |
|
JP |
|
|
Assignee: |
NIPPON ELECTRIC GLASS CO.,
LTD.
Otsu-shi, Shiga
JP
|
Family ID: |
51391019 |
Appl. No.: |
14/763178 |
Filed: |
January 9, 2014 |
PCT Filed: |
January 9, 2014 |
PCT NO: |
PCT/JP2014/050205 |
371 Date: |
July 24, 2015 |
Current U.S.
Class: |
501/32 ;
65/33.1 |
Current CPC
Class: |
C03C 3/097 20130101;
C03C 10/0027 20130101; G02B 6/12007 20130101; G02B 1/02 20130101;
C03C 2204/00 20130101; C03B 32/02 20130101 |
International
Class: |
C03C 10/00 20060101
C03C010/00; C03B 32/02 20060101 C03B032/02 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 21, 2013 |
JP |
2013-031751 |
Claims
1. A crystallized glass, wherein a value
(.DELTA.L.sub.max-.DELTA.L.sub.min)/L obtained by dividing a
difference between a maximum value .DELTA.L.sub.max and a minimum
value .DELTA.L.sub.min of .DELTA.L in a range of -40.degree. C. to
80.degree. C. by L is 8.times.10.sup.-6 or less where L represents
a length of the crystallized glass at 30.degree. C. and .DELTA.L
represents a difference between a length (L.sub.t) of the
crystallized glass at each of the temperatures and the length (L)
thereof at 30.degree. C.
2. The crystallized glass according to claim 1, wherein a local
maximum point and a local minimum point of .DELTA.L/L exist in the
range of -40.degree. C. to 80.degree. C.
3. A method for manufacturing a crystallized glass, the method
comprising the steps of: preparing a crystallizable glass; and
crystallizing the crystallizable glass to obtain a crystallized
glass, wherein a maximum temperature in the crystallization step is
a temperature according to a thermal expansion characteristic of
the crystallized glass to be obtained.
4. The method for manufacturing a crystallized glass according to
claim 3, wherein the maximum temperature in the crystallization
step is set so that a value (.DELTA.L.sub.max-.DELTA.L.sub.min)/L
obtained by dividing a difference between a maximum value .DELTA.L.
and a minimum value .DELTA.L.sub.min of .DELTA.L in a range of
-40.degree. C. to 80.degree. C. by L is 8.times.10.sup.-6 or less
where L represents a length of the crystallized glass at 30.degree.
C. and .DELTA.L represents a difference between a length (L.sub.t)
of the crystallized glass at each of the temperatures and the
length (L) thereof at 30.degree. C.
Description
TECHNICAL FIELD
[0001] The present invention relates to a crystallized glass and a
method for manufacturing the same.
BACKGROUND ART
[0002] An optical communication system using dense wavelength
division multiplex (DWDM) is conventionally used. An optical
wavelength multiplexer/demultiplexer is used for DWDM. Patent
Literature 1 describes an example thereof. The optical wavelength
multiplexer/demultiplexer described in Patent Literature 1 is
formed on a silicon substrate.
CITATION LIST
Patent Literature
[0003] [PTL 1]
[0004] JP-A-2006-284955
SUMMARY OF INVENTION
Technical Problem
[0005] What is important to the optical wavelength
multiplexer/demultiplexer is the positional accuracy between
optical elements provided therein. However, when the temperature of
the optical wavelength multiplexer/demultiplexer changes, the
relative positional relationship between the optical elements also
changes. In view of this, it is conceivable to provide, upon change
of the relative positional relationship between the optical
elements, feedback to an optical path adjusting device formed of a
MEMS (micro electro mechanical systems) mirror and so on to adjust
the optical path or to make it possible to control the optical
wavelength multiplexer/demultiplexer itself at a constant
temperature. However, such methods as just described present the
problem of increasing the size of the optical wavelength
multiplexer/demultiplexer and the problem of complicating the
control over the optical wavelength multiplexer/demultiplexer.
[0006] A principal object of the present invention is to achieve an
optical wavelength multiplexer/demultiplexer not necessarily
requiring the function of adjusting the optical path.
Solution to Problem
[0007] In a crystallized glass plate according to the present
invention, a value (.DELTA.L.sub.max-.DELTA.L.sub.min)/L obtained
by dividing a difference between a maximum value .DELTA.L.sub.max
and a minimum value .DELTA.L.sub.min of .DELTA.L in a range of
-40.degree. C. to 80.degree. C. by L is 8.times.10.sup.-6 or less
where L represents a length of the crystallized glass plate at
30.degree. C. and .DELTA.L represents a difference between a length
(L.sub.t) of the crystallized glass plate at each of the
temperatures and the length (L) thereof at 30.degree. C.
[0008] In the crystallized glass plate according to the present
invention, a local maximum point and a local minimum point of
.DELTA.L/L preferably exist in the range of -40.degree. C. to
80.degree. C.
[0009] A method for manufacturing a crystallized glass according to
the present invention includes the steps of preparing a
crystallizable glass and crystallizing the crystallizable glass to
obtain a crystallized glass. A maximum temperature in the
crystallization step is a temperature according to a thermal
expansion characteristic of the crystallized glass to be
obtained.
[0010] In the method for manufacturing a crystallized glass
according to the present invention, the maximum temperature in the
crystallization step is preferably set so that a value
(.DELTA.L.sub.max-.DELTA.L.sub.min)/L obtained by dividing a
difference between a maximum value .DELTA.L.sub.max and a minimum
value .DELTA..sub.min of .DELTA.L in a range of -40.degree. C. to
80.degree. C. by L is 8.times.10.sup.-6 or less where L represents
a length of the crystallized glass at 30.degree. C. and .DELTA.L
represents a difference between a length (L.sub.t) of the
crystallized glass at each of the temperatures and the length (L)
thereof at 30.degree. C.
Advantageous Effects of Invention
[0011] The present invention can achieve an optical wavelength
multiplexer/demultiplexer not necessarily requiring the function of
adjusting the optical path.
BRIEF DESCRIPTION OF DRAWINGS
[0012] [FIG. 1]
[0013] FIG. 1 is a schematic perspective view of a crystallized
glass according to one embodiment of the present invention.
[0014] [FIG. 2]
[0015] FIG. 2 is a graph showing .DELTA.L/L in Examples and
Comparative Examples.
[0016] [FIG. 3]
[0017] FIG. 3 is a graph showing the relationship between the
maximum temperature in a crystallization step and the value
(.DELTA.L.sub.max-.DELTA.L.sub.min)/L obtained by dividing the
difference between the maximum value .DELTA.L.sub.max and the
minimum value .DELTA.L.sub.min of .DELTA.L of an obtained
crystallized glass plate in a range of -40.degree. C. to 80.degree.
C. by L.
DESCRIPTION OF EMBODIMENTS
[0018] Hereinafter, a description will be given of an example of a
preferred embodiment for working of the present invention. However,
the following embodiment is simply illustrative. The present
invention is not at all limited to the following embodiment.
[0019] (Crystallized Glass 1)
[0020] FIG. 1 is a crystallized glass 1 for use in an optical
wavelength multiplexer/demultiplexer or the like. The crystallized
glass 1 is preferably, for example, a plate-like body and a
plate-like crystallized glass is produced by molding a molten glass
into a plate and crystallizing the plate or by molding a molten
glass into a block, crystallizing the block, cutting the block into
a plate, and polishing the plate.
[0021] As described previously, what is important to an optical
wavelength multiplexer/demultiplexer is to prevent that the
relative positional relationship between optical elements changes
with temperature change. It may be conceivable as a solution to
this, for example, to use a glass plate having a small average
coefficient of linear thermal expansion. However, the inventors
have found, as a result of their intensive studies, that even with
the use of a glass plate having a small average coefficient of
linear thermal expansion, change in relative positional
relationship between optical elements with temperature change may
not be able to be sufficiently prevented. Also, the inventors have
found that the reason for the above is that even when the average
coefficient of linear thermal expansion is small, the amount of
thermal expansion in a particular temperature range becomes
large.
[0022] To cope with this, in the crystallized glass 1, the value
(.DELTA.L.sub.max-.DELTA.L.sub.min)/L obtained by dividing the
difference between the maximum value .DELTA.L.sub.max and the
minimum value .DELTA.L.sub.min of .DELTA.L in a range of
-40.degree. C. to 80.degree. C. by L is 8.times.10.sup.-6 or less
where L represents the length of the crystallized glass 1 at
30.degree. C. and .DELTA.L represents the difference between the
length (L.sub.t) thereof at each of the temperatures and the length
(L) thereof at 30.degree. C. Therefore, at each of -40.degree. C.
to 80.degree. C. constituting a guaranteed temperature range of the
optical wavelength multiplexer/demultiplexer, the amount of
deformation upon temperature change of the crystallized glass 1 is
small. Thus, with the use of the crystallized glass 1, the relative
positional relationship between the optical elements is less likely
to change even upon temperature change. Hence, the use of the
crystallized glass 1 enables achievement of an optical wavelength
multiplexer/demultiplexer not necessarily requiring the function of
adjusting the optical path.
[0023] From the viewpoint of more effectively preventing change in
relative positional relationship between optical elements with
temperature change, (.DELTA.L.sub.max-.DELTA.L.sub.min)/L in the
range of -40.degree. C. to 80.degree. C. is preferably
6.times.10.sup.-6 or less, more preferably 5.times.10.sup.-6 or
less, still more preferably 3.times.10.sup.-6 or less, most
preferably 2.times.10.sup.-6 or less.
[0024] For reference, (.DELTA.L.sub.max-.DELTA.L.sub.min)/L of
silicon in the range of -40.degree. C. to 80.degree. C. is
300.times.10.sup.-6. (.DELTA.L.sub.max-.DELTA.L.sub.min/L of quartz
glass in the range of -40.degree. C. to 80.degree. C. is
34.times.10.sup.-6. (.DELTA.L.sub.max-.DELTA.L.sub.min/L in the
range of -40.degree. C. to 80.degree. C. of crystallized glass
containing .beta.-quartz solid solution as a predominant crystal
phase (Neoceram N-0 manufactured by Nippon Electric Glass Co.,
Ltd.) is 24.times.10.sup.-6. (.DELTA.L.sub.max-.DELTA.L.sub.min)/L
in the range of -40.degree. C. to 80.degree. C. of crystallized
glass containing .beta.-spodumene solid solution as a predominant
crystal phase (Neoceram N-11 manufactured by Nippon Electric Glass
Co., Ltd.) is 62.times.10.sup.-6.
[0025] The coefficient of thermal expansion of the crystallized
glass containing .beta.-quartz solid solution as a predominant
crystal phase (Neoceram N-0 manufactured by Nippon Electric Glass
Co., Ltd.) monotonically decreases with increasing temperature in
the temperature range of -40.degree. C. to 80.degree. C. On the
other hand, the coefficient of thermal expansion of the
crystallized glass containing .beta.-spodumene solid solution as a
predominant crystal phase (Neoceram N-11 manufactured by Nippon
Electric Glass Co., Ltd.) monotonically increases with increasing
temperature in the temperature range of -40.degree. C. to
80.degree. C. Therefore, for the crystallized glass containing only
one of 0-quartz solid solution and .beta.-spodumene solid solution
as a predominant crystal phase, it is difficult to reduce
(.DELTA.L.sub.max-.DELTA.L.sub.min)/L in the range of -40.degree.
C. to 80.degree. C. It can be believed that when crystallized glass
contains both of .beta.-quartz solid solution and .beta.-spodumene
solid solution as predominant crystal phases,
(.DELTA.L.sub.max-.DELTA.L.sub.min)/L in the range of -40.degree.
C. to 80.degree. C. of the crystallized glass can be sufficiently
reduced. It can be believed that particularly when crystallized
glass contains both of .beta.-quartz solid solution and
.beta.-spodumene solid solution as predominant crystal phases in
such a proportion that a local maximum point and a local minimum
point of .DELTA.L/L exist in the range of -40.degree. C. and
80.degree. C., (.DELTA.L.sub.max-.DELTA.L.sub.min)/L in the range
of -40.degree. C. to 80.degree. C. of the crystallized glass can be
further reduced.
[0026] (Method for Manufacturing Crystallized Glass 1)
[0027] The crystallized glass 1 can be manufactured in the
following manner.
[0028] First, a crystallizable glass for forming the crystallized
glass 1 is prepared. Next, the crystallizable glass is crystallized
to obtain a crystallized glass 1 (crystallization step).
[0029] The crystallizable glass preferably has a composition that
can precipitate both of .beta.-quartz solid solution and
.beta.-spodumene solid solution. Specifically, the preferred
composition of the crystallizable glass is, in % by mass, 55 to 75%
SiO.sub.2, 20.5 to 27% Al.sub.2O.sub.3, over 2 to 8% Li.sub.2O, 1.5
to 3% TiO.sub.2, 0.1 to 0.5% SnO.sub.2, 3.8 to 5%
TiO.sub.2+ZrO.sub.2, 3.7 to 4.5% Li.sub.2O+0.741MgO+0.367ZnO, and
up to 0.5% SrO+1.847CaO.
[0030] The inventors have found from their intensive studies that
by changing the maximum temperature in the crystallization step,
the coefficient of thermal expansion and
(.DELTA.L.sub.max-.DELTA.L.sub.min)/L of the resultant crystallized
glass 1 can be changed. In other words, the inventors have found
that crystallized glasses 1 different in
(.DELTA.L.sub.max-.DELTA.L.sub.min)/L can be obtained even from
crystallizable glass of the same composition by changing the
maximum temperature in the crystallization step. Thus, it has been
found that it is sufficient to select the maximum temperature in
the crystallization step according to the thermal expansion
characteristic of the crystallized glass to be obtained. Therefore,
in this embodiment, it is preferred to set the maximum temperature
in the crystallization step so that
(.DELTA.L.sub.max-.DELTA.L.sub.min)/L of the crystallized glass 1
in the range of -40.degree. C. to 80.degree. C. is preferably
8.times.10.sup.-6 or less, more preferably 6.times.10.sup.-6 or
less, still more preferably 5.times.10.sup.-6 or less, even more
preferably 3.times.10.sup.-6 or less, and most preferably
2.times.10.sup.-6 or less . The maximum temperature in the
crystallization step is preferably set to precipitate both of
.beta.-quartz solid solution and .beta.-spodumene solid
solution.
[0031] The reason why (.DELTA.L.sub.max-.DELTA.L.sub.min)/L of the
resultant crystallized glass 1 can be changed by changing the
maximum temperature in the crystallization step in the above manner
is not clear but can be considered as follows. It can be considered
that by changing the maximum temperature in the crystallization
step, both of .beta.-quartz solid solution and .beta.-spodumene
solid solution precipitate and the proportion of precipitation
between both the types of solid solution changes, so that
(.DELTA.L.sub.max-LL.sub.min)/L changes.
[0032] In order to facilitate the precipitation of both of
.beta.-quartz solid solution and P-spodumene solid solution in the
crystallization step, it is preferred that the rate of temperature
rise from the maximum temperature minus 100.degree. C. to the
maximum temperature be 0.05.degree. C./min to 5.degree. C./min.
[0033] The present invention will be described below in more detail
with reference to specific examples but the present invention is
not at all limited by the following examples. Modifications and
variations may be appropriately made therein without changing the
gist of the present invention.
Example 1
[0034] A raw material batch was obtained by blending and mixing raw
materials to give a composition of, in % by mass, 65.75% SiO.sub.2,
22.3% Al.sub.2O.sub.3, 3.6% Li.sub.2O, 0.7% MgO, 2.0% TiO.sub.2,
2.2% ZrO.sub.2, 1.4% P.sub.2O.sub.5, 0.35% Na.sub.2O, 0.3%
K.sub.2O, 1.2% BaO, and 0.2% SnO.sub.2. The raw material batch was
melted at 1600.degree. C. for 24 hours and then rolled into a plate
to obtain a crystallizable glass plate.
[0035] Next, the obtained crystallizable glass plate was
crystallized by subjecting it to a thermal treatment at a maximum
temperature of 925.degree. C., for 30 hours holding time at the
maximum temperature, at a rate of temperature rise of 1.degree.
C./min, and at a rate of temperature drop of 1.degree. C./min,
thereby obtaining a crystallized glass plate. The size of the
obtained crystallized glass plate was 300 mm by 300 mm by 5 mm.
[0036] Next, .DELTA.L/L values of the obtained crystallized glass
plate at -40.degree. C. to 80.degree. C. were measured. The result
is shown in FIG. 2.
Example 2
[0037] A crystallized glass plate was produced in the same manner
as in Example 1 except that the maximum temperature in the
crystallization step was 930.degree. C., and .DELTA.L/L values of
the obtained crystallized glass plate at -40.degree. C. to
80.degree. C. were measured. The result is shown in FIG. 2.
Example 3
[0038] A crystallized glass plate was produced in the same manner
as in Example 1 except that the maximum temperature in the
crystallization step was 935.degree. C., and .DELTA.L/L values of
the obtained crystallized glass plate at -40.degree. C. to
80.degree. C. were measured. The result is shown in FIG. 2.
Comparative Example 1
[0039] A quartz glass plate was prepared as Comparative Example 1
and .DELTA.L/L values thereof at -40.degree. C. to 80.degree. C.
were measured. The result is shown in FIG. 2.
Comparative Example 2
[0040] A silicon plate was prepared as Comparative Example 2 and
.DELTA.L/L values thereof at -40.degree. C. to 80.degree. C. were
measured. The result is shown in FIG. 2.
Comparative Example 3
[0041] A crystallized glass plate containing .beta.-quartz solid
solution only as a predominant crystal phase (Neoceram N-0
manufactured by Nippon Electric Glass Co., Ltd.) was prepared and
.DELTA.L/L values thereof at -40.degree. C. to 80.degree. C. were
measured. The result is shown in FIG. 2.
Comparative Example 4
[0042] A crystallized glass plate containing .beta.-spodumene solid
solution only as a predominant crystal phase (Neoceram N-11
manufactured by Nippon Electric Glass Co., Ltd.) was prepared and
.DELTA.L/L values thereof at -40.degree. C. to 80.degree. C. were
measured. The result is shown in FIG. 2.
Comparative Example 5
[0043] A crystallized glass plate was produced in the same manner
as in Example 1 except that the maximum temperature in the
crystallization step was 910.degree. C., and .DELTA.L/L values of
the obtained crystallized glass plate at -40.degree. C. to
80.degree. C. were measured. The result is shown in FIG. 2.
Comparative Example 6
[0044] A crystallized glass plate was produced in the same manner
as in Example 1 except that the maximum temperature in the
crystallization step was 940.degree. C., and .DELTA.L/L values of
the obtained crystallized glass plate at -40.degree. C. to
80.degree. C. were measured. The result is shown in FIG. 2.
[0045] Furthermore, for the crystallized glass plates obtained in
Examples 1 to 3 and Comparative Examples 5 and 6,
(.DELTA.L.sub.max-.DELTA.L.sub.min)/L in the range of -40.degree.
C. to 80.degree. C. was calculated. The results are shown in FIG.
3.
[0046] The results shown in FIGS. 2 and 3 reveal that in Examples 1
to 3 (.DELTA.L.sub.max-.DELTA.L.sub.min)/L in the range of
-40.degree. C. to 80.degree. C. is as small as 6.times.10.sup.-6 or
less and their local maximum points and local minimum points of
.DELTA.L/L exist in the range of -40.degree. C. to 80.degree. C.
Furthermore, it can be seen that by changing the maximum
temperature in the crystallization step,
(.DELTA.L.sub.max-.DELTA.L.sub.min)/L in the range of -40.degree.
C. to 80.degree. C. can be changed.
INDUSTRIAL APPLICABILITY
[0047] The crystallized glass of the present invention is not
limited to application to a substrate of an optical wavelength
multiplexer/demultiplexer but can also be used, for example, as a
spacer of an air-gap etalon, members for precision scales, such as
a linear encoder position scale, structural members of precision
equipment, and a base material for a precision mirror.
REFERENCE SIGNS LIST
[0048] 1 . . . crystallized glass
* * * * *